Wastewater lift stations are used to transfer sewage from a low level to a higher elevation. Several lift stations can be used along a sewage line to accommodate the topography of a municipality where a gravity flow to a wastewater treatment facility is not possible.
Wastewater and sewage lift stations are better known to the public because they are widely used. Such lift stations can be also used on other fluids or semi-fluid substances, and therefore, these stations are referred to herein as “lift stations”.
Although several designs of lift stations have been developed in the past, the type that is of interest herein has two submersible pumps mounted in the bottom of a well casing. The valves, flow meter and air release valves are mounted directly above the well. When the well casing is relatively small, the directional valves and other mechanical equipment stand unprotected above the well. In some other small installations, the valves and piping from the pumps and back to an discharge pipe are enclosed in a small housing mounted over the rim of the well casing. These housings are precisely fitted to enclose the piping and control equipment without leaving any excessive space inside the housing.
In other more expensive installations, all the valves, piping, meters and control equipment are mounted aboveground in a separate instrument building located near the well casing. The instrument building is built on a concrete slab as close as possible from the well casing. Piping and electrical conduits are installed underground between the well casing and the instrument building. This type of lift stations is believed to be the most popular model in use.
Examples of lift stations of the prior art or their elements are described in the following publications:
U.S. Pat. DES 197,705 issued to D. S. Ross on Mar. 17, 1964;
U.S. Pat. DES 254,509 issued to R. J. Migchelbrink, on Mar. 18, 1980;
U.S. Pat. No. 3,938,545 issued to N. Nagy et al., on Feb. 17, 1976;
U.S. Pat. No. 4,242,847 issued to R. G. Rezin on Jan. 6, 1981;
U.S. Pat. No. 4,594,153 issued to F. G. Weis on Jun. 10, 1986;
U.S. Pat. No. 6,644,342 issued to T. D. Bogan et al., on Nov. 11, 2003;
U.S. Pat. No. 7,503,339 issued to T. D. Bogan et al. On Mar. 17, 2009;
U.S. Pat. No. 8,051,873 issued to R. J. Mullen on Nov. 8, 2011;
U.S. Pat. No. 8,347,912 issued to M. Szuster et al., on Jan. 8, 2013;
CA Patent 903,178 issued to J. W. Parks on Jun. 20, 1972;
CA Patent 905,212 issued to F. G. Weis on Jul. 18, 1972.
Because of the amount of piping and electrical conduits required between a well casing and the instrument building of a lift station, it is believed that there is a need in this field for a new arrangement that is easier to build and to service than the popular installations. For example, there is a need in this field for a instrument building that is located close to the submersible pumps, so that operation of the pumps can be heard by the same person working the valves or the switches in the instrument building.
It is often the case with lift stations, that the inlet or discharge pipe needs to be dug to, inspected or replaced. Few of such cases include failure of a pipe from frost, failure from corrosion, change in topography, and upgrades to larger pipe sizes. The slab supporting the instrument building of the prior art is generally located immediately over the discharge pipe. Any access to that pipe requires the removal of the instrument building and the breaking up of the concrete slab on which the building is mounted.
It is also believed that there is a need in that field for a new lift station which allows digging down to the inlet or discharge pipe without having to demolish and replace the station itself.